Annular optical element, imaging lens module and electronic device

ABSTRACT

An annular optical element having an optical axis includes an outer diameter surface, an inner annular surface, an object-side surface and an image-side surface. The object-side surface includes an annular reflecting surface, an annular auxiliary surface and a connecting surface. The annular reflecting surface is inclined with the optical axis. The annular auxiliary surface is closer to the optical axis than the annular reflecting surface is to the optical axis. The connecting surface is for connecting to an optical element, wherein the connecting surface is closer to the optical axis than the annular auxiliary surface is to the optical axis. The image-side surface is located opposite to the object-side surface and includes an annular optical surface. A V-shaped groove is formed by the annular auxiliary surface and the annular reflecting surface of the object-side surface.

RELATED APPLICATIONS

The present application is a continuation of the application Ser. No.15/869,385, filed Jan. 12, 2018, now U.S. Pat. No. 10,514,481, whichclaims priority to Taiwan Application Serial Number 106123242, filedJul. 11, 2017, which is herein incorporated by reference.

BACKGROUND Technical Field

The present disclosure relates to an annular optical element and animaging lens module. More particularly, the present disclosure relatesto an annular optical element and an imaging lens module which areapplicable to portable electronic devices.

Description of Related Art

For the imaging lens modules equipped in the portable electronicdevices, the optical elements disposed therein can be not only the lenselements for imaging purposes, but also the annular optical elements formaintaining the proper optical spacing among the lens elements or forfixedly disposing all the lens elements in the plastic barrel.Furthermore, regarding the types of assembling an annular opticalelement in a plastic barrel, the annular optical element may be abuttedwith the adjacent lens element or a surface of the plastic barrelwithout glue dispensing, or may be fixed with the adjacent lens elementor the surface of the plastic barrel by glue dispensing.

For the annular optical element being fixed with the adjacent lenselement or the surface of the plastic barrel by glue dispensing, theglue dispensing quality may be not well, for example, unevenlydispensing, insufficiently dispensing, blocking of the glue and so onmay occur. It will result in the lens element being fixed with adeviation from the optical axis, and thereby affect the image quality ofthe entire imaging lens module. However, it is difficult to effectivelyverify the glue dispensing conditions in a narrow space between twosurfaces visually or by a conventional image inspection method, as wellas to establish an assembly acceptance criteria required for massproduction. Accordingly, how to improve imaging lens modules and theannular optical elements therein, so as to provide an effectiveinspection method for the glue dispensing quality required for massproduction, has become one of the important subjects.

SUMMARY

According to one aspect of the present disclosure, an annular opticalelement having an optical axis includes an outer diameter surface, aninner annular surface, an object-side surface and an image-side surface.The outer diameter surface surrounds the optical axis. The inner annularsurface surrounds the optical axis and forms a central hole. Theobject-side surface connects the outer diameter surface and the innerannular surface, wherein the object-side surface includes an annularreflecting surface, an annular auxiliary surface and a connectingsurface. The annular reflecting surface is inclined with the opticalaxis. The annular auxiliary surface is closer to the optical axis thanthe annular reflecting surface is to the optical axis. The connectingsurface is for connecting to an optical element, wherein the connectingsurface is closer to the optical axis than the annular auxiliary surfaceis to the optical axis. The image-side surface connects the outerdiameter surface and the inner annular surface, wherein the image-sidesurface is located opposite to the object-side surface and includes anannular optical surface. A V-shaped groove is formed by the annularauxiliary surface and the annular reflecting surface of the object-sidesurface. When an angle between the annular auxiliary surface and theannular reflecting surface is da, the following condition is satisfied:39 degrees<da<89 degrees.

According to another aspect of the present disclosure, an imaging lensmodule includes the annular optical element according to the foregoingaspect, an optical lens assembly and a plastic barrel. The optical lensassembly includes a plurality of lens elements. The lens elements aredisposed along the optical axis in the plastic barrel. The plasticbarrel includes an object-end portion, an image-end portion and a tubeportion. The object-end portion includes an outer object-end surface andan object-end opening. The image-end portion includes an outer image-endsurface and an image-end opening. The tube portion connects theobject-end portion and the image-end portion, wherein the tube portionincludes a plurality of inner parallel surfaces, at least one of theinner parallel surfaces includes a plurality of stripe structures, thestripe structures are regularly arranged along a circumferentialdirection of the inner parallel surface, and the stripe structures aredisposed correspondingly to the outer diameter surface of the annularoptical element.

According to another aspect of the present disclosure, an electronicdevice includes the imaging lens module according to the foregoingaspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a three-dimensional view of an annular optical elementaccording to the 1st embodiment of the present disclosure;

FIG. 1B is another three-dimensional view of the annular optical elementaccording to the 1st embodiment;

FIG. 1C is a plane view of the annular optical element according to the1st embodiment;

FIG. 1D is a schematic view of a cross-sectional plane along line 1D-1Dof the annular optical element according to FIG. 1C and an adjacentsurface;

FIG. 1E is a schematic view of the parameters according to FIG. 1D;

FIG. 1F is another schematic view of the parameters according to FIG.1D;

FIG. 1G is a schematic view of molds of the annular optical elementaccording to the 1st embodiment;

FIG. 2A is a schematic view of an annular optical element according tothe 2nd embodiment of the present disclosure and an adjacent surface;

FIG. 2B is a schematic view of the parameters according to FIG. 2A;

FIG. 2C is another schematic view of the parameters according to FIG.2A;

FIG. 3A is a schematic view of an annular optical element according tothe 3rd embodiment of the present disclosure and an adjacent surface;

FIG. 3B is a schematic view of the parameters according to FIG. 3A;

FIG. 3C is another schematic view of the parameters according to FIG.3A;

FIG. 4A is a schematic view of an annular optical element according tothe 4th embodiment of the present disclosure and an adjacent surface;

FIG. 4B is a schematic view of the parameters according to FIG. 4A;

FIG. 4C is another schematic view of the parameters according to FIG.4A;

FIG. 5A is a schematic view of an imaging lens module according to the5th embodiment of the present disclosure;

FIG. 5B is an enlarged view of part 5B in FIG. 5A;

FIG. 5C is a partial three-dimensional view of the imaging lens moduleaccording to the 5th embodiment;

FIG. 5D is another partial three-dimensional view of the imaging lensmodule according to the 5th embodiment;

FIG. 5E is a schematic view of an inspection image of an inspectionposition 5E in FIG. 5D;

FIG. 5F is a schematic view of another inspection image of the imaginglens module according to the 5th embodiment;

FIG. 5G is a schematic view of still another inspection image of theimaging lens module according to the 5th embodiment;

FIG. 5H is a schematic view of yet another inspection image of theimaging lens module according to the 5th embodiment;

FIG. 5I is a schematic view of further another inspection image of theimaging lens module according to the 5th embodiment;

FIG. 6A shows a schematic view of an electronic device according to the6th embodiment of the present disclosure;

FIG. 6B shows another schematic view of the electronic device accordingto the 6th embodiment;

FIG. 6C shows a block diagram of the electronic device according to the6th embodiment;

FIG. 7 shows an electronic device according to the 7th embodiment of thepresent disclosure; and

FIG. 8 shows an electronic device according to the 8th embodiment of thepresent disclosure.

DETAILED DESCRIPTION 1st Embodiment

FIG. 1A is a three-dimensional view of an annular optical element 100according to the 1st embodiment of the present disclosure, wherein theview angle of FIG. 1A is towards an object-side surface 170 of theannular optical element 100. FIG. 1B is another three-dimensional viewof the annular optical element 100 according to the 1st embodiment,wherein the view angle of FIG. 1B is towards an image-side surface 180of the annular optical element 100. In FIG. 1A and FIG. 1B, the annularoptical element 100 has an optical axis z, which is also a central axisof the annular optical element 100. The annular optical element 100includes an outer diameter surface 150, an inner annular surface 160,the object-side surface 170 and the image-side surface 180. The outerdiameter surface 150 surrounds the optical axis z. The inner annularsurface 160 surrounds the optical axis z and forms a central hole 165,i.e. the central hole 165 is enclosed by the inner annular surface 160.Furthermore, when the annular optical element 100 is applied in theimaging lens module (not shown herein), the object-side surface 170faces an imaged object of the imaging lens module, and the image-sidesurface 180 faces an image surface of the imaging lens module.

FIG. 1C is a plane view of the annular optical element 100 according tothe 1st embodiment, and FIG. 1D is a schematic view of a cross-sectionalplane along a line 1D-1D of the annular optical element 100 according toFIG. 1C and an adjacent surface R, wherein the extension of the line1D-1D passes through the optical axis z. In the 1st embodiment, theannular optical element 100 has a circularly annular shape with respectto the optical axis z. That is, all specific cross-sectional planes ofthe annular optical element 100 are the same, wherein each of thespecific cross-sectional planes passes through the optical axis z, anormal direction of each of the specific cross-sectional planes isvertical to the optical axis z, and half of each of the specificcross-sectional planes is shown as FIG. 1D. Furthermore, in order tomore clearly show the annular optical element 100 according to the 1stembodiment, the other half, which is symmetrical with the half shown inFIG. 1D relative to the optical axis z, of each of the specificcross-sectional planes is omitted in FIG. 1D. In other embodimentsaccording to the present disclosure (not shown in drawings), the annularoptical element may have a non-circularly annular shape with respect tothe optical axis.

In FIG. 1A to FIG. 1D, the object-side surface 170 connects the outerdiameter surface 150 and the inner annular surface 160, wherein theobject-side surface 170 includes an annular reflecting surface 177, anannular auxiliary surface 178 and a connecting surface 179. The annularreflecting surface 177 is inclined with the optical axis z. That is, theannular reflecting surface 177 is neither vertical nor parallel to theoptical axis z, and the annular reflecting surface 177 is a circularconical surface with respect to the optical axis z. The annularauxiliary surface 178 is closer to the optical axis z than the annularreflecting surface 177 is to the optical axis z. The connecting surface179 is for connecting to an optical element (not shown herein) of theimaging lens module, wherein the connecting surface 179 is closer to theoptical axis z than the annular auxiliary surface 178 is to the opticalaxis z. That is, the annular reflecting surface 177, the annularauxiliary surface 178 and the connecting surface 179 are formed on theobject-side surface 170 in order from the outer diameter surface 150 tothe optical axis z. Furthermore, the optical element of the imaging lensmodule may be a lens element, an imaging compensation element, a lightblocking sheet, a spacer, a retainer or so on, wherein an annularoptical element particularly indicates the spacer or the retainer.

FIG. 1E is a schematic view of the parameters according to FIG. 1D. InFIG. 1D and FIG. 1E, the image-side surface 180 connects the outerdiameter surface 150 and the inner annular surface 160, wherein theimage-side surface 180 is located opposite to the object-side surface170 and includes an annular optical surface 181. It can be said that theannular optical surface 181 is formed on the image-side surface 180. AV-shaped groove 176 is formed by the annular auxiliary surface 178 andthe annular reflecting surface 177 of the object-side surface 170.Therefore, the annular auxiliary surface 178 is advantageous to theannular optical element 100 to maintain the entire surface flatnessduring a molding process (such as an injection molding process) and anassembling process, reduce warpage and partial shrinkage of a surface,and provide the structural strength to protect the flatness and theoptical properties of the annular optical surface 181 and the annularreflecting surface 177. Moreover, the annular auxiliary surface 178 isbeneficial for the annular reflecting surface 177 to be a totalreflection surface for an inspection light L. Specifically, when theinspection light L with a specific wavelength is able to penetrate andenter into the annular optical element 100, the inspection light L fromthe outer diameter surface 150 is able to be totally reflected from theannular reflecting surface 177 and forms an image on the annular opticalsurface 181. That is, it enables the inspection light L is observedvisually or by an image inspection equipment. For example, it is shownas the inspection light L and an arrow direction thereof in FIG. 1D andFIG. 1E.

In FIG. 1D and FIG. 1E, it is further interpreted that according to theoptical principles of the total reflection, the inspection light L,which is able to penetrate and enter into the annular optical element100, is incident on the annular reflecting surface 177, and thereby theannular reflecting surface 177 is an interface between the annularoptical element 100 and the air. The annular optical element 100 withrelatively high refractive index is optically denser medium, and the airwith relatively low refractive index is optically less dense medium.When the inspection light L is incident on the annular reflectingsurface 177 with an incident angle θ being greater than a critical angleof the annular optical element 100, the inspection light L would betotally reflected from the annular reflecting surface 177. That is, theinspection light L would not be refracted to enter into the air from theannular reflecting surface 177. The incident angle θ is an angle betweenthe inspection light L and a normal direction N of the annularreflecting surface 177. The critical angle is dependent on and varieswith a wavelength of the inspection light L, a refractive index ofoptically denser medium and a refractive index of optically less densemedium, wherein the optically less dense medium for determining acritical angle of the present disclosure is the air. In addition, itshould be understood that the optical properties of the annular opticalelement 100 described in the present disclosure are not only for theinspection light L being used for inspecting the assembling quality ofthe imaging lens module, but also for light being used for otherpurposes.

When an angle (indicating the one smaller than or equal to 90 degrees)between the annular auxiliary surface 178 and the annular reflectingsurface 177 is da, that is, the angle da is defined by the V-shapedgroove 176, the following condition is satisfied: 39 degrees<da<89degrees. Therefore, it is favorable for increasing the supportingstrength of the annular optical element 100 so as to prevent the annularreflecting surface 177 from flatness being affected by an external force(such as a pressing force F in FIG. 1D and FIG. 1E) during theassembling process of the imaging lens module. Preferably, the followingcondition may be satisfied: 39 degrees<da<80 degrees.

In detail, the annular optical element 100 with the annular reflectingsurface 177 and the annular optical surface 181 may be formed integrallyand made by an injection molding method. Therefore, it is favorable forincreasing the production efficiency, and preventing the compact imaginglens module from adding additional parts and space. In other embodiments(not shown in drawings) according to the present disclosure, an annularoptical element with an annular reflecting surface and an annularoptical surface may be made by other methods, such as machining, 3Dprinting or other molding methods, but not limited thereto.

The inspection light L can be totally reflected from the annularreflecting surface 177, that is, the annular reflecting surface 177 canbe provided for the inspection light L to be totally reflectedtherefrom, wherein the inspection light L may be visible light within awavelength range from 400 nm to 700 nm or infrared light within awavelength range from 700 nm to 1000 nm. Accordingly, the inspectionlight L would be totally reflected from the annular reflecting surface177 of the annular optical element 100 according to the presentdisclosure by adjusting the inspection light L with a wavelength topenetrate and enter into the annular optical element 100, and adjustingthe inspection light L with an incident angle θ on the annularreflecting surface 177. Therefore, it is favorable for the inspectionlight L with even a weak intensity to completely transmit to the annularoptical surface 181 from the annular reflecting surface 177, so as toincrease the identification clarity of an inspection image (an image ofthe inspection light L observed on the annular optical surface 181).

The inspection light L can penetrate the annular optical surface 181,and can be reflected from the annular reflecting surface 177 to theouter diameter surface 150. That is, the annular optical surface 181 maybe provided for the inspection light L to transmit through the annularoptical surface 181, and the annular reflecting surface 177 may beprovided for the inspection light L to be reflected from the annularreflecting surface 177 to the outer diameter surface 150. Therefore, itenables that the inspection light L from the air is incident on theannular optical surface 181, and the inspection image from the annularoptical element 100 is received on the annular optical surface 181 too,so that the emitting of the inspection light L and a monitoring cameraof the image inspection equipment could operate simultaneously. It isfavorable for adjusting a source brightness of the inspection light L asneeded while observing the inspection image on the annular opticalsurface 181 by the monitoring camera, so as to enhance theidentification results of the inspection image.

Based on the descriptions of the last paragraph, the annular opticalelement 100 can provide further application. Specifically, theinspection light L can be reflected from the adjacent surface R to theouter diameter surface 150 and then to the annular reflecting surface177, and totally reflected from the annular reflecting surface 177 tothe annular optical surface 181. Thus, the structural properties of theadjacent surface R and the outer diameter surface 150 could be observedvia the inspection image on the annular optical surface 181.

More specifically, in FIG. 1D and FIG. 1E, the adjacent surface R issmooth and bright, and disposed adjacent to the outer diameter surface150. When the annular optical element 100 is assembled in a plasticbarrel of the imaging lens module, an inner surface of the plasticbarrel may be the adjacent surface R for the annular optical element100. The outer diameter surface 150 and the adjacent surface R may besubstantially parallel to each other, wherein there may be small airgaps between the outer diameter surface 150 and the adjacent surface R,or the outer diameter surface 150 and the adjacent surface R may beconnected to each other. Moreover, the annular optical element 100 canbe a retainer used for fixedly disposing a plurality of lens elements inthe plastic barrel of the imaging lens module.

When the inspection light L with a wavelength is able to penetrate andenter into the annular optical element 100, the inspection light L canbe incident on the annular optical surface 181 with an incident angleequal to or approaching zero degrees, and enter into the annular opticalelement 100, wherein the annular optical surface 181 is vertical to theoptical axis z of the annular optical element 100. Then the inspectionlight L can be incident on the annular reflecting surface 177, whereinan incident angle on the annular reflecting surface 177 of theinspection light L is greater than a critical angle of the annularoptical element 100, and the inspection light L can be totally reflectedfrom the annular reflecting surface 177 to the outer diameter surface150. An incident angle on the outer diameter surface 150 of theinspection light L is equal to or approaching zero degrees. Then theinspection light L transmits through the outer diameter surface 150 andwould be incident on the adjacent surface R with an incident angle equalto or approaching zero degrees. The path of the inspection light L, asan example, described in this paragraph is not shown in drawings, butmay be along a reverse arrow direction in FIG. 1D and FIG. 1E.

Furthermore, the adjacent surface R may have proper optical andstructural properties so that the inspection light L can be almostreflected from the adjacent surface R to the outer diameter surface 150,wherein the proper optical and structural properties can be a materialof the adjacent surface R being nontransparent to the inspection light L(i.e. a transmittance of the adjacent surface R for the inspection lightL is smaller than 50%), the adjacent surface R being smooth and bright,the adjacent surface R being parallel to the outer diameter surface 150and so on. The inspection light L reflected from the adjacent surface Rvaries with and is dependent on the structural properties of theadjacent surface R and the outer diameter surface 150, such as the sizesof the air gaps between the adjacent surface R and the outer diametersurface 150, the roughness of the adjacent surface R, the roughness ofthe outer diameter surface 150 and so on. Thus, the inspection imagesobserved on the annular optical surface 181, which are resulted from andcorresponding to different structural properties of the adjacent surfaceR and the outer diameter surface 150, have distinguishable differences.

Next, the inspection light L reflected from the adjacent surface R cantransmit through the outer diameter surface 150 with an incident angleequal to or approaching zero degrees. Then the inspection light L can beincident on the annular reflecting surface 177 with the incident angleθ, and totally reflected from the annular reflecting surface 177 totransmit through and be shown as the inspection image on the annularoptical surface 181 with an incident angle equal to or approaching zerodegrees. The path of the inspection light L, as an example, described inthis paragraph may be shown as the arrow direction in FIG. 1D and FIG.1E. Therefore, it is favorable for observing the inspection image on theannular optical surface 181 visually or by the image inspectionequipment, wherein the differences of the inspection image aredistinguishable and corresponding to different structural properties ofthe adjacent surface R and the outer diameter surface 150. Furthermore,it should be understood that the path of the inspection light Laccording to the aforementioned descriptions, FIG. 1D and FIG. 1E isjust an example among various possible paths, while an inspection lightis applied to the annular optical element 100.

In addition, it should be understood that the annular reflecting surfaceof the annular optical element according to the present disclosure isable to be a total reflection surface for an inspection light, andfurther applied in inspecting the assembling properties of any surfacewith its adjacent surface. The implemental details should not be limitedby the specific structures and materials disclosed by the annularoptical element 100 of the 1st embodiment, and incident angles onsurfaces and paths of the inspection light should not be limited bythose disclosed in FIG. 1D and FIG. 1E. Furthermore, the inspectionlight may have a smallest attenuation between being incident into andtransmitting out of the annular optical element by adjusting the relatedproperties of the annular optical element and the inspection light.Thus, in other embodiments according to the present disclosure (notshown herein), an annular optical surface of an annular optical elementmay be not vertical to an optical axis thereof. Moreover, in otherapplications of an annular optical element according to the presentdisclosure (not shown herein), incident angles on an annular opticalsurface, an outer diameter surface and an adjacent surface of aninspection light may be not zero degrees. An outer diameter surface andan adjacent surface may be not parallel to each other. Paths of theinspection light before being incident on the adjacent surface and afterbeing reflected from the adjacent surface may be different.

The V-shaped groove 176 may be tapered from the object-side surface 170towards the image-side surface 180. That is, a tapered direction of theV-shaped groove 176 is neither towards the outer diameter surface 150nor towards the inner annular surface 160. Therefore, it is favorablefor providing a proper release angle for the object-side surface 170during the injection molding process of the annular optical element 100.

FIG. 1F is another schematic view of the parameters according to FIG.1D. In FIG. 1F, when an angle (indicating the one smaller than or equalto 90 degrees) between the annular optical surface 181 and the annularreflecting surface 177 is θ1, the following condition may be satisfied:31 degrees<θ1<55 degrees. Therefore, it is favorable for maintaining thethickness of the annular optical element 100, and ensuring theinspection light L to be reflected from the annular reflecting surface177 to smoothly transmit through the annular optical surface 181.

When an angle (indicating the one smaller than or equal to 90 degrees)between the annular reflecting surface 177 and the outer diametersurface 150 is θ2, the following condition may be satisfied: 31degrees<θ2<60 degrees. Therefore, it is favorable for preventing theannular optical element 100 from thickness unevenness, which wouldresults in warpage or shrinkage of the annular optical element 100.

In FIG. 1D and FIG. 1E, the annular optical element 100 may be made of atransparent and colorless plastic material, and transparent to visiblelight. That is, a transmittance of the annular optical element 100 forvisible light is greater than 50%. Therefore, it allows visible lightwithin a wavelength range from 400 nm to 700 nm is used as theinspection light L, and it is advantageous in visually observing theinspection image and subsequently calibrating the screening criteria forthe inspection equipment to reduce the equipment misjudgments.Furthermore, it particularly indicates that the annular optical element100 is transparent to visible light with a wavelength of 587.6 nm, andthereby visible light with a wavelength of 587.6 nm can be used as theinspection light L. In the 1st embodiment, the annular optical element100 is made of a transparent and colorless plastic material, andtransparent to visible light.

In addition, the annular optical element 100 may be also transparent toinfrared light. That is, a transmittance of the annular optical element100 for infrared light is greater than 50%. Accordingly, it allowsinfrared light within a wavelength range from 700 nm to 1000 nm can beused as the inspection light L, and specifically infrared light with awavelength of 780 nm can be used. Therefore, infrared light being usedas the inspection light L is advantageous in avoiding a conflict withvisible light and thereby simultaneously inspecting the image qualityand assembling quality of the imaging lens module.

When a refractive index of the annular optical element 100 for a lightwith a wavelength of 587.6 nm (i.e. d-line) is nd, the followingcondition may be satisfied: 1.42<nd<1.68. A refractive index ndsatisfying the aforementioned range is corresponding to a smallercritical angle, and thereby it is favorable for the inspection light Lto be totally reflected in the annular optical element 100, transmitwith lower loss, and more easily transmit through the annular opticalsurface 181 after being reflected from the adjacent surface R. Inpractice, a refractive index measured for a light with a wavelength of587.56 nm may be taken as a refractive index of d-line.

When the angle between the annular reflecting surface 177 and the outerdiameter surface 150 is θ2, and a critical angle of the annular opticalelement 100 for a light with a wavelength of 780 nm is θc1, thefollowing condition may be satisfied: θ2>θc1. Therefore, it is favorablefor more completely reflecting the inspection light L via a totalreflection and thereby providing the inspection image being clearer.Furthermore, a refractive index of the annular optical element 100 for alight with a wavelength of 780 nm can be measured by a measurementsystem, and then the critical angle θc1 of the annular optical element100 for a light with a wavelength of 780 nm can be derived. Alternately,the critical angle θc1 can be obtained by an experiment. That may be, alight with a wavelength of 780 nm is incident on the annular opticalelement 100 with various incident angles one by one, and measurementsare respectively performed to verify if the total reflection occurs.Then a range or a value approaching the critical angle θc1 of theannular optical element 100 for a light with a wavelength of 780 nm canbe obtained, and if the condition of “θ2>θc1” between the angle θ2 andthe critical angle θc1 is satisfied can be subsequently verified. In the1st embodiment, the condition of “θ2>θc1” between the angle θ2 and thecritical angle θc1 is satisfied.

Specifically, the annular optical element 100 is made of a transparentand colorless plastic material, wherein refractive indices of theannular optical element 100 for lights with different wavelengths areshown as the following Table 1.1. According to Table 1.1, a criticalangle θc2 of the annular optical element 100 for a light with awavelength of 700 nm and a critical angle θc3 of the annular opticalelement 100 for a light with a wavelength of 587.56 nm can be derivedfrom the following Equation (1.1) and Equation (1.2) respectively,wherein parameter Nair represents a refractive index of the air for alight with a corresponding wavelength, parameter N-IR represents arefractive index of the annular optical element 100 for a light with awavelength of 700 nm, and parameter N-Vis represents a refractive indexof the annular optical element 100 for a light with a wavelength of587.56 nm. It should be understood critical angles of the annularoptical element 100 for lights with other wavelengths respectively canbe derived according to Equation (1.1) and Equation (1.2) by analogy,and thereby those are omitted in Table 1.1. In practice, a refractiveindex measured for a light with a wavelength of 706.519 nm may be takenas a refractive index of a light with a wavelength of 700 nm, and arefractive index measured for a light with a wavelength of 404.656 nmmay be taken as a refractive index of a light with a wavelength of 400nm.

TABLE 1.1 Annular optical element 100 of 1st embodiment Wavelength (nm)700 656.27 587.56 486.13 400 Refractive index 1.574 1.577 1.582 1.5961.618 Critical angle (deg.) 39.45 39.19

$\begin{matrix}{{\theta\; c\; 2} = {{\sin^{- 1}\left( \frac{Nair}{N - {IR}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.574} \right)} = {39.45{^\circ}}}}} & (1.1) \\{{\theta\; c\; 3} = {{\sin^{- 1}\left( \frac{Nair}{N - {Vis}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.582} \right)} = {39.19{^\circ}}}}} & (1.2)\end{matrix}$

When an Abbe number of the annular optical element 100 is Vd, thefollowing condition may be satisfied: 15<Vd<35. Therefore, the Abbenumber Vd being smaller is advantageous in achieving a better ability oflight refraction of the annular optical element 100 so as to maintainthe compact size of the annular optical element 100.

The annular optical surface 181 may have a specular property. When asurface roughness of the annular optical surface 181 is Ra1, thefollowing condition may be satisfied: 0.005a≤Ra1<0.05a. Therefore, theannular optical surface 181 being smoother is advantageous in moreeasily observing visually a connecting condition between the outerdiameter surface 150 and the adjacent surface R (such as the innersurface of the plastic barrel) so as to reduce the misjudgments.Preferably, the following condition may be satisfied: 0.005a<Ra1<0.025a.

Values of the surface roughness (Ra) commonly used with thecorresponding size range are listed as the following Table 1.2. Thesurface roughness (Ra) smaller than 0.012a approaches an ideal specularproperty, so as to be difficult to accurately measure the correspondingsize range by the common measurement systems and not to be listed inTable 1.2.

TABLE 1.2 Surface roughness (Ra) Size range (μm) Surface roughness (Ra)0.01~0.015 0.012a 0.02~0.03 0.025a 0.04~0.06 0.05a 0.08~0.11 0.1a0.17~0.22 0.2a 0.33~0.45 0.4a 0.66~0.90 0.8a

The annular reflecting surface 177 may have the specular property. Whena surface roughness of the annular reflecting surface 177 is Ra2, thefollowing condition may be satisfied: 0.005a≤Ra2<0.05a. Therefore, theannular reflecting surface 177 with a better surface property isadvantageous to the inspection light L to have less loss duringtransmitting in the annular optical element 100, and the productionefficiency to be improved while the annular reflecting surface 177 beingnot required to be plated with aluminum or silver. Preferably, thefollowing condition may be satisfied: 0.005a<Ra2<0.025a.

The outer diameter surface 150 may have the specular property. When asurface roughness of the outer diameter surface 150 is Ra3, thefollowing condition may be satisfied: 0.005a≤Ra3<0.05a. Therefore, theouter diameter surface 150 being smoother is advantageous in providingthe inspection image to be clearer. If the outer diameter surface 150has a greater surface roughness, it would affect the transmission of theinspection light L so as to result in the inspection image with a weakbrightness. Preferably, the following condition may be satisfied:0.005a<Ra3<0.025a.

Specifically, the inspection light L from the outer diameter surface 150is totally reflected from the annular reflecting surface 177 to beincident on the annular optical surface 181, wherein a surface propertyof the outer diameter surface 150 is quite similar to a surface propertyof the annular optical surface 181. Furthermore, all of the annularreflecting surface 177, the outer diameter surface 150 and the annularoptical surface 181 have the same or similar surface properties beingsmooth and bright, which are directly transferred from respectivelycorresponding surface properties of the injection molding molds, whilethe outer diameter surface 150 may have flash on edges resulted from theinjection molding molds.

In FIG. 1A to FIG. 1D, the inner annular surface 160 may include anadjusting structure 163 extended towards the image-side surface 180, andthe adjusting structure 163 is closer to the optical axis z than theannular optical surface 181 is to the optical axis z. When an angle(indicating the one smaller than or equal to 90 degrees) between theadjusting structure 163 and the optical axis z is da2, the followingcondition may be satisfied: 13 degrees<da2<45 degrees. The annularoptical element 100 is temporarily pressed by the assembling jig whilethe annular optical element 100 and other optical elements beingconnected and assembled in the imaging lens module, wherein a pressingposition on the annular optical element 100 may be shown as the pressingforce F in FIG. 1D and FIG. 1E. Therefore, the adjusting structure 163is advantageous to the annular optical element 100 to maintain theentire surface flatness during the molding process and the assemblingprocess, reduce warpage and partial shrinkage of a surface resulted froman external force. Furthermore, the adjusting structure 163 and theannular auxiliary surface 178 are able to provide the structuralstrength to protect the flatness and the optical properties of theannular optical surface 181 and the annular reflecting surface 177. Theangle da2 satisfying the aforementioned range is beneficial for thetrends of the imaging lens module with greater chief ray angle (CRA)today.

The adjusting structure 163 may include a plurality of strip-shapedstructures 164 extended from the object-side surface 170 towards theimage-side surface 180. Therefore, the structures and the shapes of thestrip-shaped structures 164 are featured with better supportingproperties, so that the annular optical surface 181 is able to withstandthe pressing force F (shown as FIG. 1D and FIG. 1E) being inevitableduring the assembling process of the imaging lens module. Furthermore,the strip-shaped structures 164 may be adjacent to the annular opticalsurface 181, so that the strip-shaped structures 164 are advantageous inmaintaining the flatness of the annular optical surface 181 during theinjection molding process of the annular optical element 100. That is,the distortion of the inspection image can be effectively decreasedwhile the dents and shrinkages of the annular optical surface 181 beingreduced. In the 1st embodiment, the adjusting structure 163 includes thestrip-shaped structures 164, and it could be said that the adjustingstructure 163 is formed with the strip-shaped structures 164. Thestrip-shaped structures 164 are extended from the object-side surface170 towards the image-side surface 180, and the adjusting structure 163with the strip-shaped structures 164 is located on the inner annularsurface 160 and the image-side surface 180 simultaneously. Thestrip-shaped structures 164 are adjacent to and slightly protruded morethan the annular optical surface 181.

Each of the strip-shaped structures 164 may have a wedge shape. Thewedge shape is a tapered end structure, which has similar effects as therelease angle concerned in the injection molding process. A plasticproduct being too thick made by a molding method may have shrinkageproblems. The wedge shape of each of the strip-shaped structures 164 isbeneficial for reducing the thickness of part related to the annularoptical surface 181, so as to reduce the shrinkage problems and increasethe flatness of the annular optical surface 181 being made by theinjection molding method, and decrease the dents and distortionsthereof. Furthermore, the strip-shaped structures 164 having wedgeshapes are featured with better supporting properties, so that it isfavorable for increasing the overall strength of the annular opticalelement 100 to withstand the force from the assembling equipment for theimaging lens module.

When a number of the strip-shaped structures 164 is N1, the followingcondition may be satisfied: 60<N1<400. Therefore, the denseness of thestrip-shaped structures 164 with the number N1 satisfying theaforementioned range are featured with better supporting properties andfavorable for effectively adjusting the flatness of the annular opticalsurface 181.

Each of the strip-shaped structures 164 may have the specular property.When a surface roughness of each of the strip-shaped structures 164 isRa4, the following condition may be satisfied: 0.005a≤Ra4<0.05a. Thestray light has been hardly generated from the adjusting structure 163with the strip-shaped structures 164. Therefore, the surface roughnessRa4 being adjusted to satisfy the aforementioned range is furtherfavorable for omitting the surface processing procedure of lightdiminishing so as to raise the production efficiency.

In FIG. 1F, a vertical parting molding structure 182 may be locatedbetween the annular optical surface 181 and the adjusting structure 163.Therefore, during the injection molding process of the annular opticalelement 100, the shape of the adjusting structure 163 is advantageous inmaintaining the flatness of the annular optical surface 181, andreducing the warpage and tilt conditions of the entire annular opticalsurface 181. Specifically, the vertical parting molding structure 182 islocated on the boundary between the annular optical surface 181 and theadjusting structure 163, and is an annular stepped structure formed bythe protruding differences between the strip-shaped structures 164 andthe annular optical surface 181 (the strip-shaped structures 164 beingprotruded more than the annular optical surface 181).

FIG. 1G is a schematic view of molds 81, 82, 83 and 84 of the annularoptical element 100 according to the 1st embodiment, wherein the otherhalves of the molds 81, 82, 83 and 84 respectively, which aresymmetrical with the halves shown in the FIG. 1G relative to the opticalaxis z, are omitted therein. In FIG. 1F and FIG. 1G, an annular moldcavity is formed by the molds 81, 82, 83 and 84, and the annular opticalelement 100 is formed in the annular mold cavity by the injectionmolding method. There is a horizontal parting surface PL1 between themolds 81 and 83, wherein the horizontal parting surface PL1 is verticalto the optical axis z and acts as a main parting surface for the annularoptical element 100. In addition, there are a vertical parting surfacePL2 between the molds 81 and 82, and a vertical parting surface PL3between the molds 83 and 84, wherein the vertical parting surfaces PL2and PL3 are both vertical to the horizontal parting surface PL1, and thevertical parting molding structure 182 is formed by the arrangement ofthe vertical parting surface PL2. The arrangements of the horizontalparting surface PL1, the vertical parting surfaces PL2 and PL3 arebeneficial to increase the dimensional accuracy of the annular opticalelement 100.

The data of the aforementioned parameters of the annular optical element100 according to the 1st embodiment of the present disclosure are listedin the following Table 1.3, wherein the parameters are also shown asFIG. 1E and FIG. 1F.

TABLE 1.3 1st embodiment da (deg.) 68 nd 1.582 da2 (deg.) 29.18 Vd 30.2θ (deg.) 45 Ra1 0.025a θ1 (deg.) 45 Ra2 0.025a θ2 (deg.) 45 Ra30.005a~0.05a θc2 (deg.) 39.45 Ra4 0.005a~0.05a θc3 (deg.) 39.19 N1 240

2nd Embodiment

FIG. 2A is a schematic view of an annular optical element 200 accordingto the 2nd embodiment of the present disclosure and an adjacent surfaceR. In FIG. 2A, the annular optical element 200 has an optical axis (notshown herein), which is also a central axis of the annular opticalelement 200. The annular optical element 200 includes an outer diametersurface 250, an inner annular surface 260, an object-side surface 270and an image-side surface 280. The outer diameter surface 250 surroundsthe optical axis. The inner annular surface 260 surrounds the opticalaxis and forms a central hole (its reference numeral is omitted).

In the 2nd embodiment, the annular optical element 200 has a circularlyannular shape with respect to the optical axis. That is, all specificcross-sectional planes of the annular optical element 200 are the same,wherein each of the specific cross-sectional planes passes through theoptical axis, a normal direction of each of the specific cross-sectionalplanes is vertical to the optical axis, and half of each of the specificcross-sectional planes is shown as FIG. 2A.

FIG. 2B is a schematic view of the parameters according to FIG. 2A, andFIG. 2C is another schematic view of the parameters according to FIG.2A. In FIG. 2A to FIG. 2C, the object-side surface 270 connects theouter diameter surface 250 and the inner annular surface 260, whereinthe object-side surface 270 includes an annular reflecting surface 277,an annular auxiliary surface 278 and a connecting surface 279. Theannular reflecting surface 277 is inclined with the optical axis. Thatis, the annular reflecting surface 277 is a circular conical surfacewith respect to the optical axis. The annular auxiliary surface 278 iscloser to the optical axis than the annular reflecting surface 277 is tothe optical axis. The connecting surface 279 is for connecting to anoptical element (not shown herein) of the imaging lens module, whereinthe connecting surface 279 is closer to the optical axis than theannular auxiliary surface 278 is to the optical axis. That is, theannular reflecting surface 277, the annular auxiliary surface 278 andthe connecting surface 279 are formed on the object-side surface 270 inorder from the outer diameter surface 250 to the optical axis.

The image-side surface 280 connects the outer diameter surface 250 andthe inner annular surface 260, wherein the image-side surface 280 islocated opposite to the object-side surface 270 and includes an annularoptical surface 281. It can be said that the annular optical surface 281is formed on the image-side surface 280. A V-shaped groove 276 is formedby the annular auxiliary surface 278 and the annular reflecting surface277 of the object-side surface 270.

In detail, the annular optical element 200 with the annular reflectingsurface 277 and the annular optical surface 281 is formed integrally andmade by an injection molding method.

The annular optical element 200 is made of a transparent and colorlessplastic material, and transparent to visible light. That is, atransmittance of the annular optical element 200 for visible light isgreater than 50%. Therefore, it allows visible light within a wavelengthrange from 400 nm to 700 nm is used as the inspection light L.Furthermore, it particularly indicates that the annular optical element200 is transparent to visible light with a wavelength of 587.6 nm, andthereby visible light with a wavelength of 587.6 nm can be used as theinspection light L.

In addition, the annular optical element 200 is also transparent toinfrared light. That is, a transmittance of the annular optical element200 for infrared light is greater than 50%. Accordingly, it allowsinfrared light within a wavelength range from 700 nm to 1000 nm can beused as the inspection light L, and specifically infrared light with awavelength of 780 nm can be used.

Specifically, the annular optical element 200 is made of a transparentand colorless plastic material, wherein refractive indices of theannular optical element 200 for lights with different wavelengths areshown as the following Table 2.1. According to Table 2.1, a criticalangle θc2 of the annular optical element 200 for a light with awavelength of 700 nm and a critical angle θc3 of the annular opticalelement 200 for a light with a wavelength of 587.56 nm can be derivedfrom the following Equation (2.1) and Equation (2.2) respectively,wherein parameter Nair represents a refractive index of the air for alight with a corresponding wavelength, parameter N-IR represents arefractive index of the annular optical element 200 for a light with awavelength of 700 nm, and parameter N-Vis represents a refractive indexof the annular optical element 200 for a light with a wavelength of587.56 nm. It should be understood critical angles of the annularoptical element 200 for lights with other wavelengths respectively canbe derived according to Equation (2.1) and Equation (2.2) by analogy,and thereby those are omitted in Table 2.1.

TABLE 2.1 Annular optical element 200 of 2nd embodiment Wavelength (nm)700 656.27 587.56 486.13 400 Refractive index 1.646 1.651 1.660 1.6831.725 Critical angle (deg.) 37.41 37.04

$\begin{matrix}{{\theta\; c\; 2} = {{\sin^{- 1}\left( \frac{Nair}{N - {IR}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.646} \right)} = {37.41{^\circ}}}}} & (2.1) \\{{\theta\; c\; 3} = {{\sin^{- 1}\left( \frac{Nair}{N - {Vis}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.66} \right)} = {37.04{^\circ}}}}} & (2.2)\end{matrix}$

The V-shaped groove 276 is tapered from the object-side surface 270towards the image-side surface 280. Each of the annular optical surface281, the annular reflecting surface 277 and the outer diameter surface250 has a specular property. When an angle between the annularreflecting surface 277 and the outer diameter surface 250 is θ2, and acritical angle of the annular optical element 200 for a light with awavelength of 780 nm is θc1, the following condition is satisfied:θ2>θc1.

The inspection light L is totally reflected from the annular reflectingsurface 277, that is, the annular reflecting surface 277 is provided forthe inspection light L to be totally reflected therefrom. Furthermore,the inspection light L is able to penetrate the annular optical surface281, and be reflected from the annular reflecting surface 277 to theouter diameter surface 250. That is, the annular optical surface 281 isprovided for the inspection light L to transmit through the annularoptical surface 281, and the annular reflecting surface 277 is providedfor the inspection light L to be reflected from the annular reflectingsurface 277 to the outer diameter surface 250.

Specifically, for example, in FIG. 2A and FIG. 2B, the adjacent surfaceR is disposed adjacent to or connected to the outer diameter surface250. When the inspection light L with a wavelength is able to penetrateand enter into the annular optical element 200, the inspection light Lis incident on the annular optical surface 281, the annular reflectingsurface 277, the outer diameter surface 250 and the adjacent surface Rin order. The path of the inspection light L, as an example, describedin this paragraph is not shown in drawings, but may be along a reversearrow direction in FIG. 2A and FIG. 2B. Moreover, the annular opticalsurface 281 is inclined with the optical axis of the annular opticalelement 200 (i.e. not vertical to the optical axis). The inspectionlight L is incident on each of the annular optical surface 281, theouter diameter surface 250 and the adjacent surface R with an incidentangle equal to or approaching zero degrees. The inspection light L isincident on the annular reflecting surface 277 with an incident angle θ,which is greater than a critical angle thereof.

Next, the inspection light L reflected from the adjacent surface R isincident on the outer diameter surface 250, the annular reflectingsurface 277 and the annular optical surface 281 in order. The path ofthe inspection light L, as an example, described in this paragraph maybe shown as an arrow direction in FIG. 2A and FIG. 2B. Moreover, theinspection light L is incident on each of the outer diameter surface 250and the annular optical surface 281 with an incident angle equal to orapproaching zero degrees. The inspection light L is incident on theannular reflecting surface 277 with an incident angle θ, which isgreater than a critical angle thereof. Therefore, it is favorable forobserving the inspection image on the annular optical surface 281visually or by the image inspection equipment, wherein the differencesof the inspection image are distinguishable and corresponding todifferent structural properties of the adjacent surface R and the outerdiameter surface 250. Furthermore, it should be understood that the pathof the inspection light L according to the aforementioned descriptions,FIG. 2A and FIG. 2B is just an example among various possible paths,while an inspection light is applied to the annular optical element 200.

In FIG. 2A to FIG. 2C, the inner annular surface 260 includes anadjusting structure 263 extended towards the image-side surface 280, andthe adjusting structure 263 is closer to the optical axis than theannular optical surface 281 is to the optical axis. Furthermore, theadjusting structure 263 is located on the inner annular surface 260 andthe image-side surface 280 simultaneously, and a surface facing theoptical axis of the adjusting structure 263 is a circular conicalsurface with respect to the optical axis. The adjusting structure 263has a light diminishing surface, wherein a size range of a surfaceroughness (Ra) of the adjusting structure 263 is 0.4 μm to 0.56 μm.

In FIG. 2B and FIG. 2C, a vertical parting molding structure 282 islocated between the annular optical surface 281 and the adjustingstructure 263. Furthermore, there is a surface (its reference numeral isomitted), which withstands a pressing force F during assembling theimaging lens module, vertical to the optical axis between the annularoptical surface 281 (not vertical to the optical axis) and the adjustingstructure 263. The vertical parting molding structure 282 is located onthe boundary between the annular optical surface 281 and the saidsurface vertical to the optical axis.

The data of the parameters of the annular optical element 200 accordingto the 2nd embodiment of the present disclosure are listed in thefollowing Table 2.2, wherein the parameters are also shown as FIG. 2Band FIG. 2C. The definitions of these parameters shown in Table 2.2 arethe same as those stated in the 1st embodiment with corresponding valuesin the 2nd embodiment.

TABLE 2.2 2nd embodiment da (deg.) 43 θc3 (deg.) 37.04 da2 (deg.) 32 nd1.660 θ (deg.) 40 Vd 20.4 θ1 (deg.) 40 Ra1 0.012a θ2 (deg.) 40 Ra20.012a θc2 (deg.) 37.41 Ra3 0.005a~0.05a

3rd Embodiment

FIG. 3A is a schematic view of an annular optical element 300 accordingto the 3rd embodiment of the present disclosure and an adjacent surfaceR. In FIG. 3A, the annular optical element 300 has an optical axis (notshown herein), which is also a central axis of the annular opticalelement 300. The annular optical element 300 includes an outer diametersurface 350, an inner annular surface 360, an object-side surface 370and an image-side surface 380. The outer diameter surface 350 surroundsthe optical axis. The inner annular surface 360 surrounds the opticalaxis and forms a central hole (its reference numeral is omitted).

In the 3rd embodiment, the annular optical element 300 has a circularlyannular shape with respect to the optical axis. That is, all specificcross-sectional planes of the annular optical element 300 are the same,wherein each of the specific cross-sectional planes passes through theoptical axis, a normal direction of each of the specific cross-sectionalplanes is vertical to the optical axis, and half of each of the specificcross-sectional planes is shown as FIG. 3A.

FIG. 3B is a schematic view of the parameters according to FIG. 3A, andFIG. 3C is another schematic view of the parameters according to FIG.3A. In FIG. 3A to FIG. 3C, the object-side surface 370 connects theouter diameter surface 350 and the inner annular surface 360, whereinthe object-side surface 370 includes an annular reflecting surface 377,an annular auxiliary surface 378 and a connecting surface 379. Theannular reflecting surface 377 is inclined with the optical axis. Thatis, the annular reflecting surface 377 is a circular conical surfacewith respect to the optical axis. The annular auxiliary surface 378 iscloser to the optical axis than the annular reflecting surface 377 is tothe optical axis. The connecting surface 379 is for connecting to anoptical element (not shown herein) of the imaging lens module, whereinthe connecting surface 379 is closer to the optical axis than theannular auxiliary surface 378 is to the optical axis. That is, theannular reflecting surface 377, the annular auxiliary surface 378 andthe connecting surface 379 are formed on the object-side surface 370 inorder from the outer diameter surface 350 to the optical axis.

The image-side surface 380 connects the outer diameter surface 350 andthe inner annular surface 360, wherein the image-side surface 380 islocated opposite to the object-side surface 370 and includes an annularoptical surface 381. It can be said that the annular optical surface 381is formed on the image-side surface 380. A V-shaped groove 376 is formedby the annular auxiliary surface 378 and the annular reflecting surface377 of the object-side surface 370.

In detail, the annular optical element 300 with the annular reflectingsurface 377 and the annular optical surface 381 is formed integrally andmade by an injection molding method.

The annular optical element 300 is made of a black plastic material, andtransparent to infrared light. That is, a transmittance of the annularoptical element 300 for infrared light is greater than 50%. Accordingly,it allows infrared light within a wavelength range from 700 nm to 1000nm can be used as the inspection light L. Therefore, the annular opticalelement 300 in the black plastic material is favorable for reducing thestray light so as not to affect the image quality of the imaging lensmodule. In addition, infrared light being used as the inspection light Lis advantageous in avoiding a conflict with visible light and therebysimultaneously inspecting the image quality and assembling quality ofthe imaging lens module. Furthermore, it particularly indicates that theannular optical element 300 is transparent to infrared light with awavelength of 780 nm, and thereby infrared light with a wavelength of780 nm can be used as the inspection light L.

Specifically, the annular optical element 300 is made of a black plasticmaterial, wherein refractive indices of the annular optical element 300for lights with different wavelengths are shown as the following Table3.1. According to Table 3.1, a critical angle θc2 of the annular opticalelement 300 for a light with a wavelength of 700 nm and a critical angleθc3 of the annular optical element 300 for a light with a wavelength of587.56 nm can be derived from the following Equation (3.1) and Equation(3.2) respectively, wherein parameter Nair represents a refractive indexof the air for a light with a corresponding wavelength, parameter N-IRrepresents a refractive index of the annular optical element 300 for alight with a wavelength of 700 nm, and parameter N-Vis represents arefractive index of the annular optical element 300 for a light with awavelength of 587.56 nm. It should be understood critical angles of theannular optical element 300 for lights with other wavelengthsrespectively can be derived according to Equation (3.1) and Equation(3.2) by analogy, and thereby those are omitted in Table 3.1.

TABLE 3.1 Annular optical element 300 of 3rd embodiment Wavelength (nm)700 656.27 587.56 486.13 400 Refractive index 1.627 1.631 1.639 1.6581.692 Critical angle (deg.) 37.92 37.6

$\begin{matrix}{{\theta\; c\; 2} = {{\sin^{- 1}\left( \frac{Nair}{N - {IR}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.627} \right)} = {37.92{^\circ}}}}} & (3.1) \\{{\theta\; c\; 3} = {{\sin^{- 1}\left( \frac{Nair}{N - {Vis}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.639} \right)} = {37.6{^\circ}}}}} & (3.2)\end{matrix}$

The V-shaped groove 376 is tapered from the object-side surface 370towards the image-side surface 380. Each of the annular optical surface381, the annular reflecting surface 377 and the outer diameter surface350 has a specular property. When an angle between the annularreflecting surface 377 and the outer diameter surface 350 is θ2, and acritical angle of the annular optical element 300 for a light with awavelength of 780 nm is θc1, the following condition is satisfied:θ2>θc1.

The inspection light L is totally reflected from the annular reflectingsurface 377, that is, the annular reflecting surface 377 is provided forthe inspection light L to be totally reflected therefrom. Furthermore,the inspection light L is able to penetrate the annular optical surface381, and be reflected from the annular reflecting surface 377 to theouter diameter surface 350. That is, the annular optical surface 381 isprovided for the inspection light L to transmit through the annularoptical surface 381, and the annular reflecting surface 377 is providedfor the inspection light L to be reflected from the annular reflectingsurface 377 to the outer diameter surface 350.

Specifically, for example, in FIG. 3A and FIG. 3B, the adjacent surfaceR is disposed adjacent to or connected to the outer diameter surface350. When the inspection light L with a wavelength is able to penetrateand enter into the annular optical element 300, the inspection light Lis incident on the annular optical surface 381, the annular reflectingsurface 377, the outer diameter surface 350 and the adjacent surface Rin order. The path of the inspection light L, as an example, describedin this paragraph is not shown in drawings, but may be along a reversearrow direction in FIG. 3A and FIG. 3B. Moreover, the annular opticalsurface 381 is vertical to the optical axis of the annular opticalelement 300. The inspection light L is incident on the annular opticalsurface 381 with an incident angle not equal to zero degrees. Theinspection light L is incident on the annular reflecting surface 377with an incident angle θ, which is greater than a critical anglethereof. The inspection light L is incident on each of the outerdiameter surface 350 and the adjacent surface R with an incident angleequal to or approaching zero degrees.

Next, the inspection light L reflected from the adjacent surface R isincident on the outer diameter surface 350, the annular reflectingsurface 377 and the annular optical surface 381 in order. The path ofthe inspection light L, as an example, described in this paragraph maybe shown as an arrow direction in FIG. 3A and FIG. 3B. Moreover, theinspection light L is incident on the outer diameter surface 350 with anincident angle equal to or approaching zero degrees. The inspectionlight L is incident on the annular reflecting surface 377 with anincident angle θ, which is greater than a critical angle thereof. Theinspection light L is incident on the annular optical surface 381 withan incident angle not equal to zero degrees. Therefore, it is favorablefor observing the inspection image on the annular optical surface 381visually or by the image inspection equipment, wherein the differencesof the inspection image are distinguishable and corresponding todifferent structural properties of the adjacent surface R and the outerdiameter surface 350. Furthermore, it should be understood that the pathof the inspection light L according to the aforementioned descriptions,FIG. 3A and FIG. 3B is just an example among various possible paths,while an inspection light is applied to the annular optical element 300.

In FIG. 3B, the annular optical surface 381 is vertical to the opticalaxis of the annular optical element 300, and the inspection light L isincident on the annular optical surface 381 with the incident angle notequal to zero degrees as an example in FIG. 3B. When an inspection imageis observed from the annular optical surface 381, the inspection imagewould be located far from the outer diameter surface 350 (i.e. towardsthe optical axis). Thus, the inspection image observed visually is likebeing not located on the annular optical surface 381. On the contrary,the inspection image observed visually from the annular optical surface181 according to the 1st embodiment is like being located on the annularoptical surface 181.

Furthermore, if the annular optical surface 381 is replaced by a virtualsubstitute surface 381 a in FIG. 3B at the design and manufacturingstages of the annular optical element 300 (i.e. the annular opticalsurface 381 being changed to the virtual substitute surface 381 a), theinspection image observed visually from the virtual substitute surface381 a would be like being located on the virtual substitute surface 381a. Specifically, an angle between the annular optical surface 381 andthe virtual substitute surface 381 a is a, the virtual substitutesurface 381 a is not vertical to the optical axis of the annular opticalelement 300, and the inspection light L is incident on the virtualsubstitute surface 381 a with the incident angle equal to or approachingzero degrees as an example in FIG. 3B.

In FIG. 3A and FIG. 3C, the inner annular surface 360 includes anadjusting structure 363 extended towards the image-side surface 380, andthe adjusting structure 363 is closer to the optical axis than theannular optical surface 381 is to the optical axis. The adjustingstructure 363 includes a plurality of strip-shaped structures 364, andit could be said that the adjusting structure 363 is formed with thestrip-shaped structures 364. The strip-shaped structures 364 areextended from the object-side surface 370 towards the image-side surface380, and the adjusting structure 363 with the strip-shaped structures364 is located on the inner annular surface 360 and the image-sidesurface 380 simultaneously. The strip-shaped structures 364 are adjacentto and slightly protruded more than the annular optical surface 381.Furthermore, each of the strip-shaped structures 364 has a wedge shapeand a specular property.

A vertical parting molding structure 382 is located between the annularoptical surface 381 and the adjusting structure 363. Specifically, thevertical parting molding structure 382 is located on the boundarybetween the annular optical surface 381 and the adjusting structure 363,and is an annular stepped structure formed by the protruding differencesbetween the strip-shaped structures 364 and the annular optical surface381 (the strip-shaped structures 364 being protruded more than theannular optical surface 381).

The data of the parameters of the annular optical element 300 accordingto the 3rd embodiment of the present disclosure are listed in thefollowing Table 3.2, wherein the parameters are also shown as FIG. 3Band FIG. 3C. The definitions of these parameters shown in Table 3.2 arethe same as those stated in the 1st embodiment with corresponding valuesin the 3rd embodiment.

TABLE 3.2 3rd embodiment da (deg.) 78 Vd 23.3 da2 (deg.) 29.18 Ra10.012a θ (deg.) 50 Ra2 0.012a θ1 (deg.) 40 Ra3 0.005a~0.05a θ2 (deg.) 50Ra4 0.005a~0.05a θc2 (deg.) 37.92 N1 240 θc3 (deg.) 37.6 α (deg.) 10 nd1.639

4th Embodiment

FIG. 4A is a schematic view of an annular optical element 400 accordingto the 4th embodiment of the present disclosure and an adjacent surfaceR. In FIG. 4A, the annular optical element 400 has an optical axis (notshown herein), which is also a central axis of the annular opticalelement 400. The annular optical element 400 includes an outer diametersurface 450, an inner annular surface 460, an object-side surface 470and an image-side surface 480. The outer diameter surface 450 surroundsthe optical axis. The inner annular surface 460 surrounds the opticalaxis and forms a central hole (its reference numeral is omitted).

In the 4th embodiment, the annular optical element 400 has a circularlyannular shape with respect to the optical axis. That is, all specificcross-sectional planes of the annular optical element 400 are the same,wherein each of the specific cross-sectional planes passes through theoptical axis, a normal direction of each of the specific cross-sectionalplanes is vertical to the optical axis, and half of each of the specificcross-sectional planes is shown as FIG. 4A.

FIG. 4B is a schematic view of the parameters according to FIG. 4A, andFIG. 4C is another schematic view of the parameters according to FIG.4A. In FIG. 4A to FIG. 4C, the object-side surface 470 connects theouter diameter surface 450 and the inner annular surface 460, whereinthe object-side surface 470 includes an annular reflecting surface 477,an annular auxiliary surface 478 and a connecting surface 479. Theannular reflecting surface 477 is inclined with the optical axis. Thatis, the annular reflecting surface 477 is a circular conical surfacewith respect to the optical axis. The annular auxiliary surface 478 iscloser to the optical axis than the annular reflecting surface 477 is tothe optical axis. The connecting surface 479 is for connecting to anoptical element (not shown herein) of the imaging lens module, whereinthe connecting surface 479 is closer to the optical axis than theannular auxiliary surface 478 is to the optical axis. That is, theannular reflecting surface 477, the annular auxiliary surface 478 andthe connecting surface 479 are formed on the object-side surface 470 inorder from the outer diameter surface 450 to the optical axis.

The image-side surface 480 connects the outer diameter surface 450 andthe inner annular surface 460, wherein the image-side surface 480 islocated opposite to the object-side surface 470 and includes an annularoptical surface 481. It can be said that the annular optical surface 481is formed on the image-side surface 480. A V-shaped groove 476 is formedby the annular auxiliary surface 478 and the annular reflecting surface477 of the object-side surface 470.

In detail, the annular optical element 400 with the annular reflectingsurface 477 and the annular optical surface 481 is formed integrally andmade by an injection molding method.

The annular optical element 400 is made of a black plastic material, andtransparent to infrared light. That is, a transmittance of the annularoptical element 400 for infrared light is greater than 50%. Accordingly,it allows infrared light within a wavelength range from 700 nm to 1000nm can be used as the inspection light L. Furthermore, it particularlyindicates that the annular optical element 400 is transparent toinfrared light with a wavelength of 780 nm, and thereby infrared lightwith a wavelength of 780 nm can be used as the inspection light L.

Specifically, the annular optical element 400 is made of a black plasticmaterial, wherein refractive indices of the annular optical element 400for lights with different wavelengths are shown as the following Table4.1. According to Table 4.1, a critical angle θc2 of the annular opticalelement 400 for a light with a wavelength of 700 nm and a critical angleθc3 of the annular optical element 400 for a light with a wavelength of587.56 nm can be derived from the following Equation (4.1) and Equation(4.2) respectively, wherein parameter Nair represents a refractive indexof the air for a light with a corresponding wavelength, parameter N-IRrepresents a refractive index of the annular optical element 400 for alight with a wavelength of 700 nm, and parameter N-Vis represents arefractive index of the annular optical element 400 for a light with awavelength of 587.56 nm. It should be understood critical angles of theannular optical element 400 for lights with other wavelengthsrespectively can be derived according to Equation (4.1) and Equation(4.2) by analogy, and thereby those are omitted in Table 4.1.

TABLE 4.1 Annular optical element 400 of 4th embodiment Wavelength (nm)700 656.27 587.56 486.13 400 Refractive index 1.574 1.577 1.582 1.5961.618 Critical angle (deg.) 39.45 39.19

$\begin{matrix}{{\theta\; c\; 2} = {{\sin^{- 1}\left( \frac{Nair}{N - {IR}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.574} \right)} = {39.45{^\circ}}}}} & (4.1) \\{{\theta\; c\; 3} = {{\sin^{- 1}\left( \frac{Nair}{N - {Vis}} \right)} = {{\sin^{- 1}\left( \frac{1}{1.582} \right)} = {39.19{^\circ}}}}} & (4.2)\end{matrix}$

The V-shaped groove 476 is tapered from the object-side surface 470towards the image-side surface 480. Each of the annular optical surface481, the annular reflecting surface 477 and the outer diameter surface450 has a specular property. When an angle between the annularreflecting surface 477 and the outer diameter surface 450 is θ2, and acritical angle of the annular optical element 400 for a light with awavelength of 780 nm is θc1, the following condition is satisfied:θ2>θc1.

The inspection light L is totally reflected from the annular reflectingsurface 477, that is, the annular reflecting surface 477 is provided forthe inspection light L to be totally reflected therefrom. Furthermore,the inspection light L is able to penetrate the annular optical surface481, and be reflected from the annular reflecting surface 477 to theouter diameter surface 450. That is, the annular optical surface 481 isprovided for the inspection light L to transmit through the annularoptical surface 481, and the annular reflecting surface 477 is providedfor the inspection light L to be reflected from the annular reflectingsurface 477 to the outer diameter surface 450.

Specifically, for example, in FIG. 4A and FIG. 4B, the adjacent surfaceR is disposed adjacent to or connected to the outer diameter surface450. When the inspection light L with a wavelength is able to penetrateand enter into the annular optical element 400, the inspection light Lis incident on the annular optical surface 481, the annular reflectingsurface 477, the outer diameter surface 450 and the adjacent surface Rin order. The path of the inspection light L, as an example, describedin this paragraph is not shown in drawings, but may be along a reversearrow direction in FIG. 4A and FIG. 4B. Moreover, the annular opticalsurface 481 is inclined with the optical axis of the annular opticalelement 400 (i.e. not vertical to the optical axis). The inspectionlight L is incident on each of the annular optical surface 481, theouter diameter surface 450 and the adjacent surface R with an incidentangle equal to or approaching zero degrees. The inspection light L isincident on the annular reflecting surface 477 with an incident angle θ,which is greater than a critical angle thereof.

Next, the inspection light L reflected from the adjacent surface R isincident on the outer diameter surface 450, the annular reflectingsurface 477 and the annular optical surface 481 in order. The path ofthe inspection light L, as an example, described in this paragraph maybe shown as an arrow direction in FIG. 4A and FIG. 4B. Moreover, theinspection light L is incident on each of the outer diameter surface 450and the annular optical surface 481 with an incident angle equal to orapproaching zero degrees. The inspection light L is incident on theannular reflecting surface 477 with an incident angle θ, which isgreater than a critical angle thereof. Therefore, it is favorable forobserving the inspection image on the annular optical surface 481visually or by the image inspection equipment, wherein the differencesof the inspection image are distinguishable and corresponding todifferent structural properties of the adjacent surface R and the outerdiameter surface 450. Furthermore, it should be understood that the pathof the inspection light L according to the aforementioned descriptions,FIG. 4A and FIG. 4B is just an example among various possible paths,while an inspection light is applied to the annular optical element 400.

In FIG. 4A and FIG. 4C, the inner annular surface 460 includes anadjusting structure 463 extended towards the image-side surface 480, andthe adjusting structure 463 is closer to the optical axis than theannular optical surface 481 is to the optical axis. The adjustingstructure 463 includes a plurality of strip-shaped structures 464, andit could be said that the adjusting structure 463 is formed with thestrip-shaped structures 464. The strip-shaped structures 464 areextended from the object-side surface 470 towards the image-side surface480, and the adjusting structure 463 with the strip-shaped structures464 is located on the inner annular surface 460 and the image-sidesurface 480 simultaneously. The strip-shaped structures 464 are adjacentto and slightly protruded more than the annular optical surface 481.Furthermore, each of the strip-shaped structures 464 has a wedge shapeand a specular property.

A vertical parting molding structure 482 is located between the annularoptical surface 481 and the adjusting structure 463. Specifically, thevertical parting molding structure 482 is located on the boundarybetween the annular optical surface 481 and the adjusting structure 463,and is an annular stepped structure formed by the protruding differencesbetween the strip-shaped structures 464 and the annular optical surface481 (the annular optical surface 481 being protruded more than thestrip-shaped structures 464).

The data of the parameters of the annular optical element 400 accordingto the 4th embodiment of the present disclosure are listed in thefollowing Table 4.2, wherein the parameters are also shown as FIG. 4Band FIG. 4C. The definitions of these parameters shown in Table 4.2 arethe same as those stated in the 1st embodiment with corresponding valuesin the 4th embodiment.

TABLE 4.2 4th embodiment da (deg.) 58 nd 1.582 da2 (deg.) 27 Vd 30.2 θ(deg.) 51 Ra1 0.025a θ1 (deg.) 51 Ra2 0.025a θ2 (deg.) 51 Ra30.005a~0.05a θc2 (deg.) 39.45 Ra4 0.005a~0.05a θc3 (deg.) 39.19 N1 240

5th Embodiment

FIG. 5A is a schematic view of an imaging lens module 5000 according tothe 5th embodiment of the present disclosure, wherein some details aboutoptical elements are omitted in FIG. 5A. Furthermore, in order to moreclearly show the imaging lens module 5000 according to the 5thembodiment, the other half, which is symmetrical with the half shown inFIG. 5A relative to the optical axis z, is omitted in FIG. 5A. In FIG.5A, the imaging lens module 5000 includes the annular optical element100 of the 1st embodiment according to the present disclosure, anoptical lens assembly 5600 and a plastic barrel 5200. The other detailsof the annular optical element 100 have been described in the foregoingparagraphs of the 1st embodiment and will not be described again herein.

FIG. 5B is an enlarged view of part 5B in FIG. 5A, and FIG. 5C is apartial three-dimensional view of the imaging lens module 5000 accordingto the 5th embodiment. In FIG. 5A to FIG. 5C, the optical lens assembly5600 includes a plurality of lens elements 5601, 5602, 5603, 5604, 5605and 5606. The lens elements 5601, 5602, 5603, 5604, 5605 and 5606 aredisposed along the optical axis z in the plastic barrel 5200. Theplastic barrel 5200 includes an object-end portion 5300, an image-endportion 5500 and a tube portion 5400. The object-end portion 5300includes an outer object-end surface 5310 and an object-end opening5311. The image-end portion 5500 includes an outer image-end surface5530 and an image-end opening 5533. The tube portion 5400 connects theobject-end portion 5300 and the image-end portion 5500, wherein the tubeportion 5400 includes a plurality of inner parallel surfaces (theirreference numerals are omitted), and the inner parallel surfaces areparallel to the optical axis z in FIG. 5A. At least one inner parallelsurface 5420 of the inner parallel surfaces includes a plurality ofstripe structures 5422. The stripe structures 5422 are slightlyprotruded on the inner parallel surface 5420 and regularly arrangedalong a circumferential direction of the inner parallel surface 5420.The stripe structures 5422 are disposed correspondingly to the outerdiameter surface 150 of the annular optical element 100, that is, theinner parallel surface 5420 including the stripe structures 5422 isdisposed correspondingly to the outer diameter surface 150. There may besmall air gaps between the inner parallel surface 5420 and the outerdiameter surface 150, and the inner parallel surface 5420 on which thestripe structures 5422 are disposed and the outer diameter surface 150may be connected to each other.

In addition, the inner parallel surface 5420, on which the stripestructures 5422 are disposed, can be taken as the adjacent surface Rapplied in the 1st embodiment according to the present disclosure. Otherdetails of the adjacent surface R and the inspection light L have beendescribed in the foregoing paragraphs of the 1st embodiment and will notbe described again herein. Therefore, it is favorable for inspecting theconnecting condition between the outer diameter surface 150 of theannular optical element 100 and the stripe structures 5422 of theplastic barrel 5200 from the annular optical surface 181. Furthermore,when the annular optical element 100 is changed to be made of a blackmaterial, it is favorable for the inspection image (i.e. the image ofthe inspection light L observed on the annular optical surface 181) tobe distinguishably shown on the annular optical surface 181 so as toincrease the identification and inspection efficiency.

Specifically, the imaging lens module 5000 includes the optical lensassembly 5600, the annular optical element 100 and an image surface5700, wherein a light passes through the optical lens assembly 5600 andimages on the image surface 5700, a position of the image surface 5700is provided for an image sensor (not shown herein) to be disposed on.The optical lens assembly 5600 includes the lens elements 5601, 5602,5603, 5604, 5605 and 5606 in order from an object side to an image-sideof the optical lens assembly 5600, wherein the optical lens assembly5600 includes a total of six lens elements (5601, 5602, 5603, 5604, 5605and 5606) and the annular optical element 100, which are disposed alongthe optical axis z in the plastic barrel 5200. The annular opticalelement 100 is a retainer, which is used for fixedly disposing the lenselements 5601, 5602, 5603, 5604, 5605, 5606 and other optical elementsbeing located thereamong in the plastic barrel 5200 of the imaging lensmodule 5000. Furthermore, the annular optical element 100 is temporarilypressed by the pressing force F of the assembling jig while assemblingthe imaging lens module, and the adjusting structure 163 and the annularauxiliary surface 178 are advantageous in providing the structuralstrength to maintain the flatness and optical properties of the annularoptical surface 181 and the annular reflecting surface 177.

The connecting surface 179 of the annular optical element 100 is forconnecting to an element connecting surface 5696 of the lens element5606, wherein both of the connecting surface 179 and the elementconnecting surface 5696 are vertical to the optical axis z.

Furthermore, the object-end portion 5300 is extended from a part of theplastic barrel 5200 for disposing the lens element 5601, being closestto the imaged object, towards the imaged object (the part of the plasticbarrel 5200 for disposing the lens element 5601 is excluded from theobject-end portion 5300). The image-end portion 5500 is extended from apart of the plastic barrel 5200 for disposing the annular opticalelement 100, being closest to the image surface 5700, towards the imagesurface 5700 (the part of the plastic barrel 5200 for disposing theannular optical element 100 is excluded from the image-end portion5500). The tube portion 5400 is between the object-end portion 5300 andthe image-end portion 5500 of the plastic barrel 5200.

FIG. 5D is another partial three-dimensional view of the imaging lensmodule 5000 according to the 5th embodiment. In FIG. 5C and FIG. 5D, theinspection light L can be incident on the annular optical surface 181 toenter into the annular optical element 100, and then the inspectionlight L is reflected from the inner parallel surface 5420, on which thestripe structures 5422 are disposed, to the annular reflecting surface177. Next, the inspection light L is totally reflected from the annularreflecting surface 177 to the annular optical surface 181, and theinspection image of the structural properties of the outer diametersurface 150 and the inner parallel surface 5420, on which the stripestructures 5422 are disposed, can be observed on the annular opticalsurface 181.

FIG. 5E is a schematic view of an inspection image of an inspectionposition 5E in FIG. 5D, and FIG. 5F is a schematic view of anotherinspection image of the imaging lens module 5000 according to the 5thembodiment. Each of the inspection images of FIG. 5E and FIG. 5F can bethe inspection image observed on any one inspection position on theannular optical surface 181 (an inspection position in FIG. 5F is notshown herein), and shows the condition of being without glue dispensingbetween the inner parallel surface 5420 and the outer diameter surface150, which are adjacent to or connected to each other.

FIG. 5E shows two stripe structure images 5422 a and 5422 bcorresponding to two of stripe structures 5422 respectively, and it isthe condition of the outer diameter surface 150 and the inner parallelsurface 5420 with the stripe structures 5422 disposed thereon being nottightly contacting each other yet. The overall inspection image in FIG.5E is bright, and the outlines of the stripe structure images 5422 a and5422 b can be slightly observed.

FIG. 5F shows two stripe structure images 5422 c and 5422 dcorresponding to two of stripe structures 5422 respectively, and it isthe condition of the outer diameter surface 150 and the inner parallelsurface 5420 with the stripe structures 5422 disposed thereon beingtightly contacting each other. The stripe structure images 5422 c and5422 d in FIG. 5F are dimmer and in black color (slash portions in thedrawing), and the outlines of the stripe structure images 5422 c and5422 d can be clearly observed. The part other than the stripe structureimages 5422 c and 5422 d, which is an image of an air gap between thetwo stripe structures 5422 (not contacting the outer diameter surface150), is brighter. FIG. 5F is corresponding to the condition that thereis the air gap therebetween, and the part of the outer diameter surface150 therebetween is not contact the inner parallel surface 5420 of theplastic barrel 5200.

FIG. 5G to FIG. 5I are respectively three schematic views of theinspection images of the imaging lens module 5000 according to the 5thembodiment. Each of the inspection images of FIG. 5G to FIG. 5I can bethe inspection image observed on any one inspection position on theannular optical surface 181 (inspection positions are not shown herein),and shows the condition of glue dispensing between the inner parallelsurface 5420 and the outer diameter surface 150.

FIG. 5G shows two stripe structure images 5422 e and 5422 fcorresponding to two of stripe structures 5422 respectively. Part of theinspection image in FIG. 5G is dimmer, and it is corresponding to thecondition of part of the outer diameter surface 150 and the stripestructures 5422 being tightly contacting each other. Another part of theinspection image in FIG. 5G is brighter, and it is corresponding to thecondition of another part of the outer diameter surface 150 contactingthe air. According to FIG. 5G, the real assembling condition of theimaging lens module 5000 may be that the annular optical element 100 istilted after assembling, and the stripe structures 5422 are not evenlypressed on the outer diameter surface 150, so that it is difficult toobserve the completed and clear outlines of the stripe structure images5422 e and 5422 f. Furthermore, an image between the stripe structureimages 5422 e and 5422 f is dimmer, and it is corresponding to thecondition that an air gap between the stripe structures 5422 is filledwith the flowing glue material of a small amount.

FIG. 5H shows two stripe structure images 5422 g and 5422 hcorresponding to two of stripe structures 5422 respectively. Part of theinspection image in FIG. 5H is dimmer, and it is corresponding to thecondition of part of the outer diameter surface 150 and the stripestructures 5422 being tightly contacting each other. Another part of theinspection image in FIG. 5H is brighter, and it is corresponding to thecondition of another part of the outer diameter surface 150 contactingthe air. According to FIG. 5H, the real assembling condition of theimaging lens module 5000 may be that the annular optical element 100 istilted after assembling, and the stripe structures 5422 are not evenlypressed on the outer diameter surface 150, so that it is difficult toobserve the completed and clear outlines of the stripe structure images5422 g and 5422 h. Furthermore, an image between the stripe structureimages 5422 g and 5422 h is dimmer, and it is corresponding to thecondition that an air gap between the stripe structures 5422 is filledwith the flowing glue material of a more amount, even the flowing gluematerial may overflow between the stripe structures 5422 and the outerdiameter surface 150.

FIG. 5I shows two stripe structure images 5422 i and 5422 jcorresponding to two of stripe structures 5422 respectively. An entiretyof the inspection image in FIG. 5I is dimmer, and it is corresponding tothe condition of the outer diameter surface 150 and the stripestructures 5422 being tightly contacting each other. According to theoutlines of the stripe structure images 5422 i and 5422 j being lessclear in FIG. 5I, the real assembling condition of the imaging lensmodule 5000 may be that the tolerance of the outer diameter surface 150is greater, so that the pressing force between the annular opticalelement 100 and the plastic barrel 5200 is greater after assembling.Furthermore, it is corresponding to the condition that an air gapbetween the stripe structures 5422 is filled with the flowing gluematerial of a great amount, even the flowing glue material may overflowbetween the stripe structures 5422 and the outer diameter surface 150.In addition, due to an entirety of the inspection image in FIG. 5I beingdimmer and without any brighter part, it should be noticed if thepressing force of part therebetween is greater or the flowing gluematerial overflows. Accordingly, it should be followed by an observationof another inspection position on the annular optical surface 181 todetermine the assembling quality of the annular optical element 100.

According to FIG. 5G to FIG. 5I, the annular optical element 100 of thepresent disclosure is advantageous in observing the assembling qualityof the imaging lens module 5000 so as to enhance the appearanceinspection efficiency to meet the production requirements. Furthermore,the inspection light L from a portion of the outer diameter surface 150is corresponding to a portion of the inner parallel surface 5420, whichis contacted or adjacent thereto, and thereby the connecting conditionbetween the portion of the outer diameter surface 150 and thecorresponding portion of the inner parallel surface 5420 can becompletely observed. When the inner parallel surface 5420 and the outerdiameter surface 150 have too different roundness and are tilted fromeach other, the portion of the outer diameter surface 150 even does notcontact the corresponding portion of the inner parallel surface 5420,wherein an inspection image thereof would be different from aninspection image of other portion of the outer diameter surface 150 byobserving on the annular optical surface 181. Therefore, it enables todetermine if the outer diameter surface 150 and the inner parallelsurface 5420 tightly contact everywhere. If there are too many portionswithout tight contact, it would be determined as an assembling fail soas to screen out the imaging lens module 5000 of assembling qualityfailure. Moreover, the acceptance criteria of the appearance orassembling quality of the imaging lens module 5000 can be defined viainspection images of four, six or other number inspection positions andthe respective occurrence ratios of the inspection images in FIG. 5G toFIG. 5I.

In addition, the annular optical surface 181 featured with being flatcan be transferred from a corresponding surface of the mold after apolish surface processing procedure. Thus, the connecting conditionbetween the portion of the outer diameter surface 150 and thecorresponding portion of the inner parallel surface 5420 being contactedor adjacent thereto can be completely observed without distortion. It isfavorable for directly observing the inspection image on the annularoptical surface 181 by the monitoring camera of the inspection equipmentto determine assembling pass or fail of the imaging lens module 5000 soas to control the assembling quality of the imaging lens module 5000.

Given the above, regarding the assembling of the annular optical elementand the plastic barrel, it is difficult to confirm the connectingcondition between the inner parallel surface (or the inner surface ofthe plastic barrel) and the annular optical element (may be theretainer), and the filling condition of the flowing glue material, whilethere are assembling techniques of accurately glue dispensing for theimaging lens module today. However, according to the annular opticalelement of the present disclosure, it enables to directly observe theinspection image on the annular optical surface being bright or dim todetermine if there are assembling failures of glue dispensing unevenly,dispensing too small amount, blocking of glue, tilt of the annularoptical element, unevenly pressing force on the annular optical elementand so on. It is favorable for supporting the review topics related tothe shipment quality of the imaging lens module so as to improve theshipment quality. In addition, the inner parallel surface having thestripe structures of the plastic barrel is favorable for thedetermination of the inspection image. Further, when infrared light isused for the inspection light, it is advantageous in maintaining theblack plastic material of both of the plastic barrel and the annularoptical element instead of changing to transparent plastic material forthe sake of the usage of the inspection light.

6th Embodiment

FIG. 6A shows a schematic view of an electronic device 10 according tothe 6th embodiment of the present disclosure, FIG. 6B shows anotherschematic view of the electronic device 10 according to the 6thembodiment, and particularly, FIG. 6A and FIG. 6B are schematic viewsrelated to a camera of the electronic device 10. In FIG. 6A and FIG. 6B,the electronic device 10 of the 6th embodiment is a smart phone, whereinthe electronic device 10 includes a camera module 11. The camera module11 includes an imaging lens module 12 according to the presentdisclosure and an image sensor 13, wherein the image sensor 13 isdisposed on an image surface (not shown in drawings) of the imaging lensmodule 12. Therefore, a better image quality can be achieved, and hencethe high-end imaging requirements of modern electronic devices can besatisfied.

Furthermore, the user activates the capturing mode via a user interface19 of the electronic device 10, wherein the user interface 19 of the 6thembodiment can be a touch screen 19 a, a button 19 b and etc. At thismoment, the imaging light is converged on the image sensor 13 of theimaging lens module 12, and the electronic signal associated with imageis output to an image signal processor (ISP) 18.

FIG. 6C shows a block diagram of the electronic device 10 according tothe 6th embodiment, and in particular, the block diagram is related tothe camera of the electronic device 10. In FIG. 6A to FIG. 6C, thecamera module 11 can further include an autofocus assembly 14 and anoptical anti-shake mechanism 15 based on the camera specification of theelectronic device 10. Moreover, the electronic device 10 can furtherinclude at least one auxiliary optical component 17 and at least onesensing component 16. The auxiliary optical component 17 can be a flashmodule for compensating for the color temperature, an infrared distancemeasurement component, a laser focus module and etc. The sensingcomponent 16 can have functions for sensing physical momentum andkinetic energy, and thereby can be an accelerator, a gyroscope, and aHall effect element, to sense shaking or jitters applied by hands of theuser or external environments. Accordingly, the functions of theautofocus assembly 14 and the optical anti-shake mechanism 15 of thecamera module 11 can be aided and enhanced to achieve the superior imagequality. Furthermore, the electronic device 10 according to the presentdisclosure can have a capturing function with multiple modes, such astaking optimized selfies, high dynamic range (HDR) under a low lightcondition, 4K resolution recording, etc. Additionally, the user canvisually see the captured image of the camera through the touch screen19 a and manually operate the view finding range on the touch screen 19a to achieve the auto focus function of what you see is what you get.

Furthermore, in FIG. 6B, the camera module 11, the sensing component 16and the auxiliary optical component 17 can be disposed on a flexibleprinted circuit board (FPC) 77 and electrically connected with theassociated components, such as the imaging signal processor 18, via aconnector 78 to perform a capturing process. Since the currentelectronic devices, such as smart phones, have a tendency of beingcompact, the way of firstly disposing the camera module and relatedcomponents on the flexible printed circuit board and secondlyintegrating the circuit thereof into the main board of the electronicdevice via the connector can satisfy the requirements of the mechanicaldesign and the circuit layout of the limited space inside the electronicdevice, and obtain more margins. The autofocus function of the cameramodule can also be controlled more flexibly via the touch screen of theelectronic device. In the 6th embodiment, the electronic device 10includes a plurality of sensing components 16 and a plurality ofauxiliary optical components 17. The sensing components 16 and theauxiliary optical components 17 are disposed on the flexible printedcircuit board 77 and at least one other flexible printed circuit board(its reference numeral is omitted) and electrically connected with theassociated components, such as the image signal processor 18, viacorresponding connectors to perform the capturing process. In otherembodiments (not shown herein), the sensing components and the auxiliaryoptical components can also be disposed on the main board of theelectronic device or carrier boards of other types according torequirements of the mechanical design and the circuit layout.

In addition, the electronic device 10 can further include but not belimited to a wireless communication unit, a control unit, a storageunit, a random access memory, a read-only memory, or a combinationthereof.

7th Embodiment

FIG. 7 shows an electronic device 20 according to the 7th embodiment ofthe present disclosure. The electronic device 20 of the 7th embodimentis a tablet personal computer. The electronic device 20 includes animaging lens module 22 according to the present disclosure.

8th Embodiment

FIG. 8 shows an electronic device 30 according to the 8th embodiment ofthe present disclosure. The electronic device 30 of the 8th embodimentis a wearable device. The electronic device 30 includes an imaging lensmodule 32 according to the present disclosure.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. It is to be noted thatTables show different data of the different embodiments; however, thedata of the different embodiments are obtained from experiments. Theembodiments were chosen and described in order to best explain theprinciples of the disclosure and its practical applications, to therebyenable others skilled in the art to best utilize the disclosure andvarious embodiments with various modifications as are suited to theparticular use contemplated. The embodiments depicted above and theappended drawings are exemplary and are not intended to be exhaustive orto limit the scope of the present disclosure to the precise formsdisclosed. Many modifications and variations are possible in view of theabove teachings.

What is claimed is:
 1. An annular optical element, having an opticalaxis and comprising: an outer diameter surface surrounding the opticalaxis; an inner annular surface surrounding the optical axis and forminga central hole; an object-side surface connecting the outer diametersurface and the inner annular surface, wherein the object-side surfacecomprises: a reflecting surface inclined with the optical axis; anauxiliary surface, wherein the auxiliary surface is closer to theoptical axis than the reflecting surface is to the optical axis; and aconnecting surface for connecting to an optical element, wherein theconnecting surface is closer to the optical axis than the auxiliarysurface is to the optical axis; and an image-side surface connecting theouter diameter surface and the inner annular surface, wherein theimage-side surface is located opposite to the object-side surface andcomprises an optical surface; wherein a V-shaped groove is formed by theauxiliary surface and the reflecting surface of the object-side surface,an angle between the optical surface and the reflecting surface is θ1,and the following condition is satisfied:31 degrees<θ1<55 degrees.
 2. The annular optical element of claim 1,wherein the annular optical element with the reflecting surface and theoptical surface is formed integrally and made by an injection moldingmethod.
 3. The annular optical element of claim 2, wherein an anglebetween the reflecting surface and the outer diameter surface is θ2, andthe following condition is satisfied:31 degrees<θ2<60 degrees.
 4. The annular optical element of claim 3,wherein the angle between the reflecting surface and the outer diametersurface is θ2, a critical angle of the annular optical element for alight with a wavelength of 780 nm is θc1, and the following condition issatisfied:θ2>θc1.
 5. The annular optical element of claim 4, wherein the annularoptical element is made of a black plastic material and transparent toan infrared light.
 6. The annular optical element of claim 4, whereinthe annular optical element is made of a transparent and colorlessplastic material, and transparent to a visible light.
 7. The annularoptical element of claim 2, wherein a refractive index of the annularoptical element for a light with a wavelength of 587.6 nm is nd, and thefollowing condition is satisfied:1.42<nd<1.68.
 8. The annular optical element of claim 2, wherein an Abbenumber of the annular optical element is Vd, and the following conditionis satisfied:15<Vd<35.
 9. The annular optical element of claim 2, wherein theV-shaped groove is tapered from the object-side surface towards theimage-side surface.
 10. The annular optical element of claim 2, whereinthe inner annular surface comprises an adjusting structure extendedtowards the image-side surface, the adjusting structure is closer to theoptical axis than the optical surface is to the optical axis, an anglebetween the adjusting structure and the optical axis is da2, and thefollowing condition is satisfied:13 degrees<da2<45 degrees.
 11. The annular optical element of claim 10,wherein a vertical parting molding structure is located between theoptical surface and the adjusting structure.
 12. The annular opticalelement of claim 10, wherein the adjusting structure comprises aplurality of strip-shaped structures extended from the object-sidesurface towards the image-side surface.
 13. The annular optical elementof claim 12, wherein each of the strip-shaped structures has a wedgeshape.
 14. The annular optical element of claim 13, wherein each of thestrip-shaped structures has a specular property, a surface roughness ofeach of the strip-shaped structures is Ra4, and the following conditionis satisfied:0.005a≤Ra4<0.05a.
 15. The annular optical element of claim 12, wherein anumber of the strip-shaped structures is N1, and the following conditionis satisfied:60<N1<400.
 16. The annular optical element of claim 2, wherein theoptical surface has a specular property, a surface roughness of theoptical surface is Ra1, and the following condition is satisfied:0.005a≤Ra1<0.05a.
 17. The annular optical element of claim 2, whereinthe reflecting surface has a specular property, a surface roughness ofthe reflecting surface is Ra2, and the following condition is satisfied:0.005a≤Ra2<0.05a.
 18. The annular optical element of claim 2, whereinthe outer diameter surface has a specular property, a surface roughnessof the outer diameter surface is Ra3, and the following condition issatisfied:0.005a≤Ra3<0.05a.
 19. The annular optical element of claim 2, whereinthe optical surface is provided for an inspection light to transmittherethrough, and the reflecting surface is provided for the inspectionlight to be reflected from the reflecting surface to the outer diametersurface.
 20. The annular optical element of claim 2, wherein thereflecting surface is provided for an inspection light to be totallyreflected therefrom.
 21. An imaging lens module, comprising: the annularoptical element of claim 1; an optical lens assembly comprising aplurality of lens elements; and a plastic barrel, wherein the lenselements are disposed along the optical axis in the plastic barrel, andthe plastic barrel comprises: an object-end portion comprising an outerobject-end surface and an object-end opening; an image-end portioncomprising an outer image-end surface and an image-end opening; and atube portion connecting the object-end portion and the image-endportion, wherein the tube portion comprises a plurality of innerparallel surfaces, at least one of the inner parallel surfaces comprisesa plurality of stripe structures, the stripe structures are regularlyarranged along a circumferential direction of the inner parallelsurface, and the stripe structures are disposed correspondingly to theouter diameter surface of the annular optical element.
 22. An electronicdevice, comprising: the imaging lens module of claim 21.